The present invention relates to an instrument panel structure with an airbag unit, which is provided at a front end portion in a vehicle cabin.
Conventionally, it is well known that an airbag unit with an airbag that is inflated to protect a passenger seated in an assistant seat at a vehicle frontal crash is provided inside an instrument panel that is provided at a front end portion in a vehicle cabin. Herein, the following structure, as disclosed, for example, in Japanese Patent Laid-Open Publication No. 2005-088634, is known. That is, a lid portion is formed on an upper face portion of the instrument panel at a portion corresponding to the airbag unit, wherein the lid-portion is partitioned by a tear line with a groove that is formed on an inside face of the upper portion and configured to open when the tear line is torn by an inflation pressure of the airbag. And, a frame portion is attached to the inside face of the upper portion, wherein the frame portion is configured to enclose an inflation space of the airbag between the airbag unit and the lid portion. Herein, the lid portion is connected to the frame portion via a hinge member at a front end portion of the lid portion. The above-described structure has an advantage of providing a good appearance and a smooth opening of the lid portion. That is, there may be substantially no changes in level, color and the like on the surface of the instrument panel. Further, the lid portion is configured to open, when the tear line is torn by an inflation pressure of the airbag, forward substantially around the hinge member, without any scatter of broken pieces of the lid portion.
Meanwhile, it is known recently, from a designing aspect of the instrument panel, to provide a difference-in-level portion that is formed on the upper face portion of the instrument panel at a central portion of the upper face portion in a vehicle longitudinal direction so as to extend laterally along an entire vehicle width. Herein, a rear portion of the upper portion that is located in back of the difference-in-level portion is located at a lower level than a front portion of the upper portion that is located in front of the difference-in-level portion. And, some meters and the like are provided at a portion that interconnects the front upper face portion and the rear upper face in front of a driver's seat. Furthermore, it is known that a vertical position of the front upper face portion of the instrument panel is adjustable so that there can be provided a state with some difference-in-level and a flat state with substantially no difference-in-level, as disclosed, for example, in Japanese Patent Laid-Open Publication No. 2005-247245.
Herein, in providing the airbag unit inside the instrument panel with the above-described difference-in-level, there may be a problem of a location of the airbag unit. Namely, in a case where the airbag unit is provided inside the front upper face portion of the instrument panel, the location of the airbag unit would be away from the passenger seated in the assistant seat, so that the inflation timing of the airbag would be somewhat delayed for the passenger. Meanwhile, in a case where the airbag unit is provided at a rear portion inside the rear upper face portion of the instrument panel, the airbag would be inflated so rearward that a front end portion of the airbag would not be inflated properly in a space between a windshield and the upper face portion of the instrument panel. As a result, there would occur a relatively large gap between the front end portion of the airbag and front ends of the windshield or the upper face portion of the instrument panel when the airbag is inflated to its maximum opening state. This gap may cause a forward shift of the inflated airbag by the passenger hitting against the airbag, so that the protection of the passenger by the airbag would be improperly delayed. Although the airbag with a large volume could prevent this delayed protection, such airbag would require an improperly long time for its full inflation instead.
Thus, it may be considered that the airbag unit is provided inside the front end portion (near the difference-in-level portion) of the rear upper face of the instrument panel. Herein, however, there is a concern that the lid portion opening forward would hit against the difference-in-level portion and thereby stop opening further. Accordingly, the front end portion of the airbag would be prevented from opening forward, so that, likewise, there would occur the gap between the front end portion of the airbag and front ends of the windshield or the upper face portion of the instrument panel when the airbag is inflated to its maximum opening state, which would delay the protection of the passenger by the airbag improperly. There is also a concern that the lid portion would be broken and pieces of the broken lid portion would scatter.